Dry ice refrigerator



Dec. 28, 1965 J. J. WULFKEN 3,225,558

DRY ICE REFRIGERATOR F'led Jan. 28, 1964 2 Sheets-Sheet 1 i@ @Mb ATTORNEY DeC- 28, 1965 J.J. WULFKEN DRY ICE REFRIGERATOR 2 Sheets-Sheet 2 Filed Jan. 28, 1964 FIG. 3

IN VEN TOR. JsepJ/l/a/fkw/ A T TORNEV United States Patent 3,225,558 Patented Dec. 28, i965 ffice 3,225,558 v DRY ICE REFRGERTR Joseph li. Wulfken, Plainview, N.Y., assigner to Ref Eynamies Corporation, Mineoia, NKY., a corporation of New York Filed Jan. 28, 1964, Ser. No. 340,768 6 Claims. (Ci. 62--167) This invention relates to a refrigerator and, more particularly, to a refrigerator that utilizes Dry Ice.

It is an object and purpose of the invention to provide a portable refrigerator in which the refrigerator is capable of use as integral part of a food galley of the type commonly employed in such vehicles as aircraft, trains, buses, and the like.

Another object of the invention is to provide -a refrigerator that can operate without the need for electrical power and yet is able to retain foods at predetermined desired temperatures over prolonged periods by the use of Dry Ice.

Still another object of the invention resides in th-e simplicity of details of structure that results in an extremely efficiently operating, relatively simple refrigerator, that can function within desired temperature ranges without being affected by the altitude or by the attitude or position of the vehicle in which it is mounted. A feature of the invention resides in a unique arrangement of a refrigerating circuit that provides a continuous metering of the temperature to constantly retain the temperature within desired tolerances.

Other and further objects of this invention reside in the structures and arrangements hereinfater more fully described with reference to the accompanying drawings in which:

FIG. l is a front perspective view of ra refrigerator constructed according to the teaching of the invention,

FIG. 2 is a perspective View of the refrigeration circuit or system,

FIG. 3 is a cross-section of the flow control device taken in the direction of lines 3-3 of FIG. 2, and

FiG. 4 is a cross-section of FIG. 3 taken along lines 4 4.

Referring now to the drawings, the refrigerator thereshown is generally identihed by the numeral 10. It comprises a cabinet 12 and a refrigerating system or circuit generally identified by the numeral 14 and as more fully shown in FIG. 2. The refrigerator cabinet l2 is illustrated in FIG. 1 of the drawing as including a pair of upper compartments 16 and 1S, each of which extends along the top and into the cabinet and each of which is adapted to accommodate a tray of Dry Ice.

Also included in the refrigerator cabinet 12 is a pair of freezer compartments 20 and 22. These are located directly beneath the dry ice compartments 16 and f3. Beneath the freezer compartments 29 and 22 is another pair of cold compartments 24 and 26. In practice, the freezer compartments 20 and 22 are adapted to contain trays of food in frozen condition and to retain the same in such condition for a desired period of time. On the other hand, the cold compartments 24 and Z are intended to retain foods in a cold condition, but not in a frozen condition. lt will be recognized by those skilled in the art that `all the compartments 16 to 2f; inclusive have a covering door not shown. The doors are normally intended to be closed. However, the same are eliminated vfrom the drawings to enable a fuller unencumbered View and clearer explanation of the refrigerator 1G and its interior refrigeration system or circuit 14.

Mounted within the cabinet 12 is a refrigerating systern or circuit generally identified by the numeral 14 and as more fully shown in FIG. 2. The refrigerator system 14 comprises a pair or a plurality of substantially horizontally disposed relatively spaced condenser tanks or reservoirs 23 and 3i? arranged in parallel relationship and that are adapted to contain and house an adequate supply of a iiuid refrigerant, as Freon. Each of the tanks 28 and 30 is connected with the other by a plurality of communicating tubes 32 that are positioned at the lowermost portions of the tanks to insure a free flow between and passing movement of the refrigerant from one tank to the other. Thus, irrespective of the attitude of the vehicle in which the refrigerator 1t) is mounted, refrigerating fluid will always flow through the refrigerating circuit 14 to be described.

The combination of the tanks 2S, 39 and the connecting passageways 32 defines a heat exchanger that is adapted to be cooled by the Dry Ice contained in the compartments le and i3 positioned directly thereabove. Each of the tanks 28 and 3) has a drain tube 34 that is connected thereto at the lowermost portion and at the corner of the same, thus insuring that the refrigerant in the bottom of the tank will always flow through at least one of the tubes 34. Each of the drain tubes 34 extends downward `and terminates at a T-shaped junction 36. Thus, regardless of the attitude of the vehicle, refrigerating fluid will always ow from at least one corner of one of the tanks 28 or 3i) through its lowermost positioned drain tube 34 to the T-shaped junction 36. The T-shaped junction 36 is connected with a flow control device generally identiiied by the numeral 38.

The tiow control device 3S is more fully illustrated in FIGS. 3 and 4. It comprises a covering 39 that has an upstanding valve housing 4t) in which the tube 36 is mounted to supply the refrigerating fluid downward thereto. An outlet drain tube 42 is also connected with the housing 40 for fluid communication with the inlet tube 36. However, mounted for movement Within the housing 40 is a valve element 44 that operates in the nature of a needle valve to permit the opening and closing of the passage of refrigerating liuid from the tube 36 to the tube 42 or t0 permit the regulation and partial varying or metering of the passage of fluid from the tube 35 to the tube 42 to carefully meter the amount of refrigerating fluid that can be communicated from the one tube to the other.

Threadedly mounted for adjustment in the lower end of the valve element 44 is an adjustment screw 46 that is adapted to be adjusted at the factory. The head of the screw 46 is adapted to rest against the bottom of a resilient bellows 4S that tends to constantly fall away from the valve element 44 to permit the valve to fall away from its normally closed position as shown in FIG. 3.

Forming a part of the flow control device 38 is a thermostatic control or temperature sensing element 56 that has a capillary tube 52 which is connected in communication with the interior of a chamber 54 on the cover 39. The temperature sensing element 5t) is adapted to be positioned adjacent the lowermost surface of either one of the freezer compartments Ztl or Z2 to sense the temperature therein. It contains a volatile fluid that is temperature sensitive to apply a vapor pressure. The volatile tiuid is in constant communication with the chamber 54 in which a displaceable diaphragm 56 is mounted. The diaphragm 56 is displaceably movable in response to the variations in pressure exerted against it by the temperature sensitive volatile fluid.

Positioned beneath and in contact with the diaphragm S6 is an actuator pin or stud 58 that bears at its lowermost point against a bearing surface 59 provided on a lever ci? pivoted at its one end 62 and having a work performing threaded adjustment screw 64 at its other end. The lever is normally moved upward about its pivot o2 into engagement with the actuator pin 58 as a result of the force applied thereagainst by a spring 66. The force with which the spring 66 causes the lever 60 to pivot is variable or adjustable by the threaded adjustment of a screw 68 mounting a spring seat '70. The force of the spring 66 bearing against the lever 60 causes the screw 64 to contract the bellows 48, thereby constantly urging the valve 44 into its closed position as shown in FIG. 3.

Positioned between the freezer compartments 2t) and 22 and the cold compartments 24 and 26 is an evaporator or cold plate 72 that is adapted to receive and contain the refrigerant uid from the reservoirs or tanks 28 and 30 by way of the drain tubes 36 and 42 as controlled and metered by the ow control device 38. The refrigerant enters the cold plate 72 by way of the tube 74. The refrigerating circuit is completed by a return conduit or connection 76 that serves to connect the cold plate 72 with the top or uppermost portion of at least one of the tanks 28 and 30. The whole system 14 is charged with the uid refrigerant by way of a filler tube 78 that is later crimped closed to prevent the loss or leakage of fluid therefrom.

In operation, the spring pressure applied to the lever 60 is preset by adjusting the screw 68 thereby permitting the lever 60 to move only in response to a predetermined force that might be applied against the diaphragm 56 by the volatile Huid in the sensing element 50. The sensing element 50 is positioned in one of the compartments or 22 at a location thereof in which it is desired to have a predetermined constantly controlled temperature. The adjustment screw 64 is similarly adjusted as is the adjustment screw 46 to cause the valve 44 to remain in its normally closed condition as shown in FIG. 3 when the temperature in the compartments 20 and 22 are within a desired range.

During operation, the compartments 16 and 18 are charged with trays of Dry Ice. The Dry Ice cools the heat exchanger structure which includes the tanks 28 and 30 and the connecting tubes 32 and the refrigerant therein. The refrigerant in the tanks 28 and 3Q is in liquid form and ows downwardly from the corners 34 thereof through the drain tubes to the junction 35 and then into the housing 40. When the temperature in the freezer compartments 2t) and 22 is above that selected by the adjustment of the spring 66 previously described, the volatile fluid in the sensing element Sil applies a vapor pressure in the chamber S4 against the diaphragm 56 displacing the same downward to move the actuator pin 58 against the lever 60. As the pressure applied by the fluid in the sensing element 50 exceeds the resistance of the spring 66, the lever 60 is pivoted downwardly about its pivot 62. This displaces the adjustment screw 64 away from the bellows 48, thereby permitting the bellows to expand.

The valve element 44 moves correspondingly downward with the expanding bellows 48 to uncover the drain tube 36 an amount in accordance with or corresponding to the pressure of the fluid in the sensing element 50 applied to the diaphragm 56. This permits the liquid refrigerant to ow from the heat exchanger, through the tube 36 to the housing 40, about valve 44, the connecting tube 42, and from there by way of the tube 74 to the evaporator or cold plate 72. As the cold refrigerant liquid moves about and within the plate 72, it cools the compartments 20 and 22 as well as the compartments 24 and 26 therebelow. The upper portion of the compartments 20 and 22 are cooled by the heat exch-anger structure 28, 30 and 32.

This action keeps the freezer compartments 20 and 22 at the desired temperature as predetermined by the setting of the spring pressure 66. The flow control device 38 is a continually operating mechanism that will close, open or partially open the communication of the refrigerant from the heat exchanger to the cold plate. This serves to retain an even and constant control of the temperature wherever the sensing element 50 is located. When the temperature in the compartments 20 and 22 warms, the liquid in the cold plate evaporates in the form of a gas. The gas rises along the return tube 76 to enter the top of tank 30. There, the gas is once again cooled, condensed and changed back to liquid form for recirculation throughout the system.

It will be clear that upon the initial operation of the refrigerating system 14, a free flow of chilled refrigerant will move through the housing 40 about the needle valve 44 from the heat exchanger to the cold plate 72 until the temperature of the cold plate and the adjacent sensing element 5t) drops to a point of stabilization which will be the desired temperature. At this stabilized temperature, the volatile liquid in the sensing element 50 will cool and contract to exert a negative pressure on the diaphragm 56 to enable closure or partial closure of the needle valve 44. This partial closure of the needle valve 44 allows just enough refrigerant to flow from the heat exchanger to the cold plate to maintain the compartments at a steady desired temperature.

Thus, the temperature in the compartments 20 and 22 is regulated by the rate of flow which the valve 44 allows the chilled refrigerant to pass from the heat exchanger to the cold plate. Naturally, if the rate of flow of the refrigerant is high, the cold plate will chill more rapidly, If the rate of flow is controlled to permit a small, but almost continuous amount of refrigerant to move from the heat exchanger to the cold plate, the temperature in the compartments 20 and 22 will remain substantially constant. The unique structural details of the flow control device 38 permits the continuous control and regulation of flow of the refrigerant.

While there have been shown and described and pointed out the fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art, without departing from the spirit of the invention. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.

I claim:

1. In a refrigerator, a refrigeration cabinet having a compartment to be refrigerated and a compartment adapted to contain Dry Ice, a refrigeration circuit including a plurality of reservoirs containing a refrigerant beneath said Dry Ice compartment, a cooling plate beneath said compartment to be refrigerated, means connecting said reservoirs together to permit the free flow of said refrigerant therebetween, means connecting said plate with a portion of at least one of said plurality of reservoirs for the communication of said refrigerant from said cooling plate to said reservoirs, drain means connecting said reservoirs with said cooling plate to supply said refrigerant thereto; and a control device connected with said drain means to control the communication of said refrigerant from said reservoirs to said cooling plate, said device including a valve operatively movable in said drain means to control the movement of said refrigerant from said reservoirs to said cooling plate, operable means in said compartment to be refrigerated to apply a force in accordance with the temperature therein, and means to transmit the force from said operable means to said valve to cause the same to operatively move in said drain means to control the amount of said refrigerant communicated from said reservoirs to said cooling plate.

2. in a refrigerator employing a circulating fluid refrigerant, the combination of at least two horizontally disposed reservoirs substantially parallel to each other for retaining the refrigerant, a plurality of cooling tubes connecting said reservoirs and permitting the free ow of the refrigerant therebetween, a plurality of drain tubes connected to said reservoirs to drain the refrigerant therefrom, a valve connected to said drain tubes to regulate the flow of said refrigerant therethrough, a temperature sensing element to sense changes in temperature, a volatile fluid in said sensing element and having a temperature sensitive vapor pressure, a flexible diaphragm movably responsive to the changes in the vapor pressure of said volatile fluid, means for transmitting the movement of said diaphragm to said Valve to move the same to regulate the ilow of the refrigerant through said drain tubes, and a cold plate connected to said drain tubes to receive the iluid refrigerant therefrom and being connected with said reservoirs to convey the iluid refrigerant therefrom to said reservoirs.

3. In a refrigerator employing a circulating lluid refrigerant, the combination of a plurality of substantially horizontally disposed reservoirs for retaining the refrigerant, a plurality of tubes connecting said reservoirs and permitting the free flow of the refrigerant therebetween, a plurality of downwardly depending drain tubes connected to said reservoirs to drain the refrigerant there from, a cold plate connected to said drain tubes to receive the fluid refrigerant therefrom, conduit means connecting said cold plate to the upper side of one of said plurality of reservoirs to convey the fluid refrigerant therefrom to said one of said reservoirs, a thermostatically controlled valve structure connected to said drain tubes between said reservoirs and cold plate to regulate the llow of the fluid refrigerant from said reservoirs to said cold plate, said valve structure including a valve element operable in said drain tubes to close and variably open the same, and means to cause said valve element to operate in response to variations in temperatures.

4. In a refrigerator employing a circulating lluid refrigerant, the combination of two horizontally disposed tanks for retaining the refrigerant, means connecting said tanks and permitting the free flow of the refrigerant therebetween, means for maintaining a supply of Dry Ice adjacent to said tanks to cool the same, a plurality of drain tubes each connected to the underside of a respective one of said tanks to drain the refrigerant downward from said tanks, a cold plate below said tanks and connected to said drain tubes to receive the fluid refrigerant therefrom, and conduit means connecting said cold plate to the upper side of one of said tanks to convey the fluid refrigerant from said cold plate to said one of said tanks.

5. In a refrigerator employing a circulating iluid refrigerant, the combination of a tank containing a fluid refrigerant, means for maintaining a supply of Dry Ice adjacent to said tank to cool the fluid refrigerant therein, a cold plate below said tank completely and below said means for maintaining the supply of Dry Ice, a drain connecting said tank with said cold plate to convey the tluid refrigerant downward therefrom to said cold plate, a valve interposed in said drain to regulate the llow of refrigerant therethrough, a temperature sensing element between said means for maintaining the supply of Dry Ice and said cold plate to sense changes in temperature, a

volatile fluid in said sensing element and developing a temperature sensitive Vapor pressure, a chamber independent of and spaced from said drain, a capillary tube connected at one end to said temperature sensing element and at the other end to said chamber to enable the vapor pressure from said sensing element to be transmitted to said chamber, flexible diaphragm means movably responsive to the changes in the vapor pressure in said chamber, a yieldably resistant pivoted lever interconnecting said diaphragm with said valve for transmitting the movement of said diaphragm to said valve to move the same to regulate the flow of the refrigerant through said drain, and means connecting said cold plate to said tank to convey the fluid refrigerant therefrom to said tank.

6. In a refrigerator employing a circulating iluid refrigerant, the combination of a plurality of horizontally disposed tanks substantially parallel to each other for retaining the refrigerant, a plurality of tubes connecting the undersides of said tanks and permitting the free flow of the refrigerant therebetween, means for maintaining a supply of Dry Ice adjacent to said tanks to cool the same, a plurality of downwardly depending drain tubes each connected to the underside of a respective one of said tanks near the ends thereof to drain the refrigerant from said tanks, a valve connected to said drain tubes to regulate the ilow of said refrigerant therethrough, a temperature sensing element to sense changes in temperature, a volatile lluid in said sensing element and having a temperature sensitive vapor pressure, a chamber, a capillary tube connected at one end to said temperature sensing element and at the other end to said chamber t0 enable the vapor pressure from said sensing element to be transmitted to said chamber, a flexible diaphragm movably responsive to the changes in the vapor pressure in said chamber, a yieldably resistant pivoted lever, means for transmitting the movement of said diaphragm to said lever to pivot the same, a movable bellows, means for transmitting the pivoting movement of said lever to move said bellows, said bellows being connected with said valve to move the same to regulate the llow of said refrigerant through said drain tubes, a cold plate connected to said drain tubes to receive the fluid refrigerant therefrom, and means connecting said cold plate to the upper side of one of said tanks to convey the lluid refrigerant therefrom to said one of said tanks.

References Cited by the Examiner UNITED STATES PATENTS 1,618,815 2/1927 Cory et al 62-223 X 2,636,357 4/1953 Woods 62-332 X 3,172,271 3/1965 Dubois et al. 62-168 ROBERT A. OLEARY, Primary Examiner,

MEYER PERLIN, Examiner.

N. R. WILSON, Assistant Examiner. 

4. IN A REFRIGERATOR EMPLOYING A CIRCULATING FLUID REFRIGERANT, THE COMBINATION OF TWO HORIZONTALLY DISPOSED TANKS FOR RETAINING THE REFRIGERANT, MEANS CONNECTING SAID TANKS AND PERMITTING THE FREE FLOW OF THE REFRIGERANT THEREBETWEEN, MEANS FOR MAINTAINING A SUPPLY OF DRY ICE ADJACENT TO SAID TANKS TO COOL THE SAME, A PLURALITY OF DRAIN TUBES EACH CONNECTED TO THE UNDERSIDE OF A RESPECTIVE ONE OF SAID TANKS TO DRAIN THE REFRIGERANT DOWNWARD FROM SAID TANKS, A COLD PLATE BELOW SAID TANKS AND CONNECTED TO SAID DRAIN TUBES TO RECEIVE THE FLUID REFRIGERANT THEREFROM, AND CONDUIT MEANS CONNECTING SAID COLD PLATE TO HE UPPER 